The genetic diversity of Bradyrhizobium japonicum in soils of the soybean growing regions of western Canada and the northern United States

Abstract

Introduction of early maturing cultivars of soybean ( Glycine max [L.] Merr.) in western Canada has dramatically increased soybean production in the region. Soybean grows in symbiotic association with rhizobia which carry out biological nitrogen fixation in the plant. Previous studies have shown that rhizobium populations evolve quickly in the soil. In this study, we have examined the genetic diversity of 107 Bradyrhizobium japonicum isolates from the soybean growing areas in western Canada and the northern United States (North Dakota, South Dakota and Minnesota) by rep-PCR genomic fingerprinting techniques--(REP-PCR) and (ERIC-PCR). Results of our study shows that the B. japonicum isolates are genetically diverse. Our results also point towards the influence of agricultural practices and geographical origin of isolates on genetic diversity of B. japonicum populations. Our results also suggest that sandy soil texture could have negative influence on genetic diversity of B. japonicum populations at site Elm Creek in Manitoba.